[FFmpeg-trac] #7784(undetermined:new): ffmpeg/lavf changes the case of metadata keys

FFmpeg trac at avcodec.org
Sun Mar 10 20:27:47 EET 2019


#7784: ffmpeg/lavf changes the case of metadata keys
-------------------------------------+-------------------------------------
               Reporter:  Cigaes     |                  Owner:
                   Type:  defect     |                 Status:  new
               Priority:  minor      |              Component:
                Version:  git-       |  undetermined
  master                             |               Keywords:
             Blocked By:             |               Blocking:
Reproduced by developer:  0          |  Analyzed by developer:  0
-------------------------------------+-------------------------------------
 Start with an Ogg Vorbis file with the reference tags:
 {{{
 head -c $[44100*4*60] /dev/zero > silence.pcm
 oggenc -r -B 16 -C 2 -R 44100 -a Artist -t Title -l Album -c
 custom=Comment silence.pcm
 }}}

 Then use ffmpeg to remux the file:
 {{{
 ./ffmpeg_g -i /tmp/silence.ogg -y -c copy /tmp/silence_ff.ogg
 }}}

 Check the output:
 {{{
 $ vorbiscomment silence.ogg
 custom=Comment
 title=Title
 artist=Artist
 album=Album
 $ vorbiscomment silence_ff.ogg
 CUSTOM=Comment
 TITLE=Title
 ARTIST=Artist
 ALBUM=Album
 encoder=Lavf58.26.101
 }}}

 The spec https://xiph.org/vorbis/doc/v-comment.html states that the keys
 are case-insensitive, but ffmpeg should nonetheless try to match the
 workings of the reference implementation, and/or not change things without
 a good reason.

 Output of the ffmpeg command-line (does not contain any useful
 information):
 {{{
 ffmpeg version N-93308-g1144d5c96d Copyright (c) 2000-2019 the FFmpeg
 developers
   built with gcc 8 (Debian 8.3.0-2)
   configuration: --enable-shared --disable-static --enable-gpl --enable-
 libx264 --enable-libopus --enable-libass --enable-libfreetype --enable-
 opengl --assert-level=2
   libavutil      56. 26.100 / 56. 26.100
   libavcodec     58. 47.103 / 58. 47.103
   libavformat    58. 26.101 / 58. 26.101
   libavdevice    58.  6.101 / 58.  6.101
   libavfilter     7. 48.100 /  7. 48.100
   libswscale      5.  4.100 /  5.  4.100
   libswresample   3.  4.100 /  3.  4.100
   libpostproc    55.  4.100 / 55.  4.100
 Input #0, ogg, from '/tmp/silence.ogg':
   Duration: 00:01:00.00, start: 0.000000, bitrate: 1 kb/s
     Stream #0:0: Audio: vorbis, 44100 Hz, stereo, fltp, 112 kb/s
     Metadata:
       CUSTOM          : Comment
       TITLE           : Title
       ARTIST          : Artist
       ALBUM           : Album
 Output #0, ogg, to '/tmp/silence_ff.ogg':
   Metadata:
     encoder         : Lavf58.26.101
     Stream #0:0: Audio: vorbis, 44100 Hz, stereo, fltp, 112 kb/s
     Metadata:
       CUSTOM          : Comment
       TITLE           : Title
       ARTIST          : Artist
       ALBUM           : Album
       encoder         : Lavf58.26.101
 Stream mapping:
   Stream #0:0 -> #0:0 (copy)
 Press [q] to stop, [?] for help
 size=      11kB time=00:00:59.99 bitrate=   1.4kbits/s speed=5.97e+03x
 video:0kB audio:3kB subtitle:0kB other streams:0kB global headers:4kB
 muxing overhead: 318.329468%
 }}}

--
Ticket URL: <https://trac.ffmpeg.org/ticket/7784>
FFmpeg <https://ffmpeg.org>
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